I posted a while ago about problems getting the OrangeRX DRX R618XL receiver working.
After more investigation, it turns out that the OrangeRX receiver does work, but only for a short period if time (20-30 seconds), before getting “choppy” (working intermittently), and then cutting out completely. The only way to recover is to unplug/replug the receiver to power cycle it, at which point the same thing happens. This seems to happen faster/more if I am moving the sticks (and controlling servos) rather than leaving them down/neutral. It seem to take longer if the rover is not armed (servos not moving/drawing power), but does happen after several minutes.
I realized this after trying a different receiver - Power Up RD810 - which works as expected (with the small annoyance of not persisting in PPM mode between shutdown/restart, requiring manual configuration every time.)
With the RD810, I can see the Radio Channels changing as expected and
cat /sys/kernel/rcio/rcin/ch2 is ~1102 with the throttle low and ~1974 high. Servos also move as expected. This leads me to believe the Navio2 hardware, software, and setup (servo power etc.) are all fine. (In the short times when the OrangeRX receiver is working, it’s values are ~1053 and ~1893 respectively.)
My best theories for why the OrangeRX would behave like this are 1) Overheating (it does feel rather warm to touch) 2) Timing issue with the ppm framerate getting our of sync 3) A bug in handling 6-ch frames vs. 8-channels 4) Some functionality of the receiver where it stops outputting if it receives the same inputs for too long.
Given the above behavior of the issue occurring faster when the servos are moving, yet the nothing going wrong for extended periods of time with the RD810 receiver moving the servos, I am led to believe the problem is either with the OrangeRX receiver itself, or some complex interaction with the receiver and the servo busses. If so, there’s not much that can be done here, other than document it so others can be aware and not waste their time debugging.
-Spektrum DX6i transmitter
-Servo rail draws 0.4A @ 6V
-Testing with two micro-sized hobby servos on outputs 1 and 3 which draw <0.25A combined.